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Sodium in Oil Analysis - 72: good, bad or ugly?

afroman

New member
Hi - longtime lurker, first time poster. Am looking at an straight inboard powered 25 footer for sale. I'm in the survey process now. The engine is advertised as a Merc 350 inboard, but the holley carb leads me to believe it might be a PCM or Indmar or another. Anyway, the real question is this: oil analysis returned sodium at 72 which lab says is abnormal. Brief research on the intertubes tells me 1-50 is normal.

Is this a managable problem or a big concern?

Engine got a good bill of health from the marine mechanic who assessed it. He noted minor corrosion on the manifold/riser gasket joint. Blowby was good/great levels, so no issues there. Other than a tuneup and managing a 10-year old engine with 690 hours, he said in good shape. The engine is a 350 raw water cooled.

Not sure how to tell if the 72 is related to old oil (with additives) or a cracked head or just an old gasket or salt from the aforementioned gasket on the riser.

Just trying to put that 72 in perspective and determine if that alone is a deal breaker.

Everything else checked out ok.

Thanks!
 
Thanks! I saw the general research saying that, but since it's raw water cooled what i'm trying to grapple with is the extent of the problem at that reading level and to determine the extent / severity of the problem. Appreciate the help!
 
First time test? What type of oil is it, brand and weight?

Did they find any traces of water in the oil? I would not worry about this. If you decide to purchase the vessel, when you change the oil send a sample of the new unused oil off for testing so you have a base(control) to compare to.
 
boat had been winterized, was un winterized for a sea trial and tests. believe oil sat a bit, my mechanic who surveyed the engine said oil was dirty. no mention of water in oil. no other telltales beyond the minor corrosion at riser gasket.

no temp issues, doesn't appear to burn oil. just the sodium count. not sure how much is 'acceptable' before in need to worry.
 
whoops. yes, was first time test after a few months of sitting. don't believe oil had been changed yet to start the season.

many thanks.
 
What if you were to contact a lab who does this routinely?
They know exactly what to expect from certain oils and certain engines.

.
 
good suggestion. my engine mechanic/surveyor did this and i have that perspective. Was trying to broaden that view to others. thanks again.
 
Can you now see how scattered about your requested information is being handed to you?
A tab bit in one thread.... and a tab bit in another thread.

Suggestion #2:
Choose a thread that you want to stick with.
Create a hyperlink to that thread.
Post the hyperlink in the other threads with a notation that directs everyone back to THAT thread!

Suggestion only! :D
 
72 could be someone pouring in oil with a funnel that was just used for antifreeze. change oil, run for an hour, resample.
 
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